INTRODUCTION: Degeneration associated with aging is physiological and is not necessarily symptomatic. Some individuals over the age of 80 years have no cervical symptoms whatsoever and lead healthy lives. Observing the cervical X‐rays of these healthy elders provides the key to identifying the difference between physiological degeneration and degeneration that induces neurological symptoms, and has the potential to provide new information on the pathology of cervical spondylotic myelopathy. This study focused on healthy elders over the age of 80 and elders who manifest neurological symptoms, and compared their cervical X‐ray pictures and their personal information with the aim of identifying the characteristics of physiological degeneration that do not induce neurological symptoms.
METHODS: Two groups of subjects were selected: 50 “super healthy elders” over the age of 80 years (80 to 93 years) who had no past history of cervical related symptoms and who still lead independent, healthy lives without receiving any aid or nursing care (37 men and 23 women), and a “neurological symptom group” of 52 elderly patients over the age of 80 (80 to 86 years) who had neurological symptoms clearly related to cervical pathology (39 men and 23 women). The two groups were compared for cervical X‐ray findings such as degeneration of interspinal discs, spur formation, diameter of the spinal canal, and alignment of the spine, as well as family history of longevity, diet, exercise, career history, and the presence of systemic complication(s). The subjects consented to have their information published, in accordance with the Helsinki Declaration.
RESULTS: Degeneration of the cervical spine was noted in “super healthy elders” as well as in the neurological symptom group. They showed no significant difference from the symptomatic group in terms of degeneration of interspinal discs and spur formation, etc., in both men and women. The “super healthy elders” showed little or no physiological lordosis, with the majority having a linear and/or kyphotic cervical alignment. None of the “super healthy elders” suffered spondylolisthesis, but 60% showed spontaneous fusion of vertebral bodies and ossification of the anterior longitudinal ligament. The average diameter of the spinal canal at level C5 was 13.2 mm for men and 12.4 mm for women in the neurological symptom group, but was significantly larger in the “super healthy elders”, with an average of 16.7 mm for men and 15.3 mm for women. If deaths due to accidents or acts of war were excluded, 96% of the “super healthy elders” had a family history of longevity. Their parents had no history of cervical disease. Although no differences were seen between the two groups in terms of career history and diets, a significant difference was seen in terms of exercise, with the “super healthy elders,” especially women, having had a significantly higher rate of past participation in sports activities.
CONCLUSION: Even “super healthy elders” who maintained ideal health showed cervical degeneration. They manifested changes which reduced the range of movement of the cervical spine, such as narrowing of the interspinal disc, spur formation, and ossification of the anterior longitudinal ligament. These findings were similar to those seen in the interspinal discs of cervical vertebrae in mice in an animal experiment that we conducted in which bone spurs (osteophytes) were induced after bone morphogenetic protein (BMP) had appeared in the enthesis. Degeneration may induce neurological symptoms when stenosis of the spinal canal is present, and our study has shown that the developmental stenosis is closely related to a person's genetic background. Research on induction of physiological degeneration is just as important as research on suppression of cervical degeneration caused by aging.
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